Clinical and photobiological response in eight patients with solar urticaria under treatment with omalizumab, and review of the literature

Quality of life measurement in urticaria: Position statement of the European Academy of Dermatology and Venereology Task Forces on Quality of Life and Patient-Oriented Outcomes and Urticaria and Angioedema

The European Academy of Dermatology and Venereology (EADV) Task Forces on quality of life (QoL) and patient-oriented outcomes and on urticaria and angioedema recommendations for the assessment of Health-related (HR) QoL in all patients with urticaria in research and practice are as follows: to use the DLQI for adults and the CDLQI for children as dermatology-specific and the CU-Q2oL as a disease-specific HRQoL instruments in urticaria; to use generic instruments to provide comparison of data on urticaria with non-dermatologic diseases, or to compare with healthy volunteers or the general population; to select validated HRQoL instruments with appropriate age limits; to present exact numeric data for HRQoL results; correct title of any HRQoL instrument should be used, along with its correct abbreviation and the reference to its original publication, where possible. The EADV TFs discourage the use of non-validated HRQoL instruments and modified HRQoL instruments that have not undergone standard validation.

Solar urticaria involves rapid mast cell STAT3 activation and neutrophil recruitment, with FcεRI as an upstream regulator

BACKGROUND

Solar urticaria is a rare photodermatosis characterized by rapid-onset sunlight-induced urticaria, but its pathophysiology is not well understood.

OBJECTIVE

We sought to define cutaneous cellular and molecular events in the evolution of solar urticaria following its initiation by solar-simulated UV radiation (SSR) and compare with healthy controls (HC).

METHODS

Cutaneous biopsy specimens were taken from unexposed skin and skin exposed to a single low (physiologic) dose of SSR at 30 minutes, 3 hours, and 24 hours after exposure in 6 patients with solar urticaria and 6 HC. Biopsy specimens were assessed by immunohistochemistry and bulk RNA-sequencing analysis.

RESULTS

In solar urticaria specimens, there was enrichment of several innate immune pathways, with striking early involvement of neutrophils, which was not observed in HC. Multiple proinflammatory cytokine and chemokine genes were upregulated (including IL20, IL6, and CXCL8) or identified as upstream regulators (including TNF, IL-1β, and IFN-γ). IgE and FcεRI were identified as upstream regulators, and phosphorylated signal transducer and activator of transcription 3 expression in mast cells was increased in solar urticaria at 30 minutes and 3 hours after SSR exposure, suggesting a mechanism of mast cell activation. Clinical resolution of solar urticaria by 24 hours mirrored resolution of inflammatory gene signature profiles. Comparison with available datasets of chronic spontaneous urticaria showed transcriptomic similarities relating to immune activation, but several transcripts were identified solely in solar urticaria, including CXCL8 and CSF2/3.

CONCLUSIONS

Solar urticaria is characterized by rapid signal transducer and activator of transcription 3 activation in mast cells and involvement of multiple chemotactic and innate inflammatory pathways, with FcεRI engagement indicated as an early event.

Solar Urticaria: An Ambispective Study in a Long-term Follow-up Cohort with Emphasis on Therapeutic Predictors and Outcomes

Solar urticaria is a rare photodermatosis with several unknown pathogenic, clinical and therapeutic aspects. This study analysed the clinical and therapeutic features of a long-term follow-up solar urticaria cohort, with a focus on omalizumab management and outcomes, and characterized omalizumab response with the use of the high-affinity immunoglobulin E (IgE) receptor (FcεRI) and the Urticaria Control Test. An observational, unicentric, ambispective study was conducted from 2007 to 2023. Solar urticaria was diagnosed in 41 patients with a median follow-up of 60 months. Thirteen patients were prescribed omalizumab, with a median treatment time of 48 months. A significant decrease in FcεRI baseline levels and subsequent median increase in Urticaria Control Test was evidenced after omalizumab prescription in all patients. Drug survival at 48 months was at 88.9%. Omalizumab stepping-down protocol led to sustained omalizumab discontinuation in only 1 patient. Median basal Urticaria Control Test was lower (p < 0.01) in patients who were prescribed omalizumab and in patients without remission. This study contributes to our knowledge of omalizumab outcomes in real-life clinical practice and highlights the pathogenic importance of IgE-mediated pathways in solar urticaria, where FcεRI emerges as a possible biomarker of omalizumab response.

Incapacitating solar urticaria: successful treatment with omalizumab

Solar urticaria is a rare form of physical urticaria mediated by immunoglobulin E. The lesions appear immediately after the sun exposure, interfering with the patient's normal daily life. Omalizumab, a monoclonal anti-IgE antibody, has been recently approved for the treatment of chronic spontaneous urticaria, and the latest reports support its role also in the treatment of solar urticaria. Hereby, we report a case of solar urticaria refractory to conventional treatment strategies, with an excellent response to treatment with omalizumab and phototesting normalization.

Solar urticaria - An Australian case series of 83 patients

Solar urticaria (SU) is a rare form of urticaria with a pathogenesis that is poorly understood. It affects all skin types, can be difficult to diagnose, and is challenging to manage effectively. We conducted a retrospective review of patients with SU in our institution. A total of 83 patients (56 females) were identified as having SU. The mean age was 32 years (7-74) at first development of symptoms/signs of SU. Pruritus was the most common symptom reported (79%). Of the 60 patients who underwent monochromator testing at least once, 35 had SU confirmed with most reacting to visible light and UVA, or to UVA alone. Antihistamines and sun avoidance remain the mainstay treatment for SU but other treatments, including omalizumab, are of potential interest in treating patients with recalcitrant SU. The characterisation of this large case series of patients may help dermatologists recognise and manage this rare disorder appropriately.

Update on Omalizumab for Urticaria: What's New in the Literature from Mechanisms to Clinic

PURPOSE OF REVIEW

Since omalizumab has been approved for urticaria, numerous randomized and real-life observational trials have been published. We reviewed the period January 2017-February 2018.

RECENT FINDINGS

Omalizumab is effective for the control of urticaria recalcitrant to antihistamines in different populations globally. The ratio of total serum IgE 4-week/baseline ≥2 can predict response with a high likelihood. In observational real-life trials, doses have been adjusted on an individual basis: in some populations, up to two-thirds of the patients can be controlled with 150 mg/month; however, others are still not controlled with 300 mg/month. In these, 150 mg bimonthly could be tried, before up-dosing to 450 mg/month. On the long run (up to 3 years) omalizumab kept its efficacy. In many patients, dosing intervals could be augmented (6-8 weeks, some even more). After a 12-month treatment, about 20% showed long-term remission without relapse. Some biomarkers are being detected. Adjusting omalizumab doses in urticaria patients could enhance efficacy (shortening dosing interval and/or augmenting dose) and save costs (after 12 months: extending dosing interval and/or reducing dose).

Immunoglobulin E-Mediated Autoimmunity

The study of autoimmunity mediated by immunoglobulin E (IgE) autoantibodies, which may be termed autoallergy, is in its infancy. It is now recognized that systemic lupus erythematosus, bullous pemphigoid (BP), and chronic urticaria, both spontaneous and inducible, are most likely to be mediated, at least in part, by IgE autoantibodies. The situation in other conditions, such as autoimmune uveitis, rheumatoid arthritis, hyperthyroid Graves’ disease, autoimmune pancreatitis, and even asthma, is far less clear but evidence for autoallergy is accumulating. To be certain of an autoallergic mechanism, it is necessary to identify both IgE autoantibodies and their targets as has been done with the transmembrane protein BP180 and the intracellular protein BP230 in BP and IL-24 in chronic spontaneous urticaria. Also, IgE-targeted therapies, such as anti-IgE, must have been shown to be of benefit to patients as has been done with both of these conditions. This comprehensive review of the literature on IgE-mediated autoallergy focuses on three related questions. What do we know about the prevalence of IgE autoantibodies and their targets in different diseases? What do we know about the relevance of IgE autoantibodies in different diseases? What do we know about the cellular and molecular effects of IgE autoantibodies? In addition to providing answers to these questions, based on a broad review of the literature, we outline the current gaps of knowledge in our understanding of IgE autoantibodies and describe approaches to address them.